1. Technical Field
The invention relates to dispensing equipment and in particular to a portable gun for dispensing metered and mixed plural component liquids. More particularly, the invention relates to such a portable dispensing gun for plural component liquids in which the plural components are metered and mixed adjacent to the point of dispensing.
2. Background Information
An ever-increasing number of products used in everyday life require the dispensing of liquid materials in one form or another for their manufacture. These liquids typically comprise two-component reactive resins, but one-part materials also are often used. The types of materials dispensed include virtually any movable liquid or paste such as epoxies, polyurethanes, silicones, polyesters, acrylics, polysulfides and phenolics. The processes in which such materials are used include filling precise amounts of mixed resin into molds, encapsulating electrical components with insulating resins, applying continuous beads of structural adhesives, injecting polyesters into closed molds, sealing joints with two-part polysulfides, and numerous other functions requiring accurate material control. Examples of product applications for these materials and processes include under-the-hood electronic assemblies and safety devices for the automotive industry; encapsulation of magnetic and other advanced electrical devices for the aerospace industry; component mounting, security potting and glob-top applications for circuit board assemblies; and switches, power supplies, heating assemblies and other electronic components for the appliance industry.
Thus, as the above-described materials continue to be consumed in increasing quantities, the demand for precision liquid dispensing equipment is also growing. The industry is continually searching for more reliable, efficient and accurate liquid metering, mixing and dispensing equipment. For example, a particular application may require that a machine efficiently and accurately dispense materials ranging from less than one cc to many gallons. However, although the industry is calling for more exacting machine performance, it is also requiring that the equipment design be simple, straightforward and capable of being operated by production personnel or conveniently integrated with automation devices such as robots and conveyor systems. Problems currently exist because many prior art metering, mixing and dispensing machines are immobile, requiring that the work be brought to the machine, which often is inefficient and impractical.
Moreover, the design of many of the prior art metering, mixing and dispensing machines, due to their bulky nature and resultant inability to position the machines in close proximity to the work, include lengthy hoses for transport of the metered and/or mixed material, the components of which often begin to react sometime before it is actually dispensed, which is undesirable. Rather, it is preferable that the material be metered and mixed as close as possible to the point of dispensing, to avoid premature reaction of the materials. Also, locating the metering and mixing components of the machine as close as possible to the dispensing point increases metering accuracy.
The closest known prior art to my liquid metering, mixing and dispensing gun is the proportionate metering unit manufactured by Naka Seiki Co., Ltd., of Japan. However, the structure of this unit is completely different than any improved dispensing gun.
Thus, the need exists for an improved liquid metering, mixing and dispensing machine in which plural component materials are metered and mixed adjacent to the point of dispensing thereof, and which is portable enough to be handled by a human operator or easily integrated with automation systems.